A performance index called an FOM (figure of merit) is employed to determine the performance of a semiconductor chip or a semiconductor module having a plurality of semiconductor chips therein.
The FOM is represented by an equation incorporating electrical characteristics of on-resistance, charge density, and the like in order to determine the electrical performance of a semiconductor chip or a semiconductor module. By using a value of an FOM gained by substituting a specific value of the electrical characteristic into the FOM equation, individual performance of the semiconductor chip or the semiconductor module is determined, or performance of one chip/module is compared with that of another semiconductor chip/module.
For instance, Japanese Unexamined Patent Publication No. 2000-156503 (paragraph 0006) discloses that an FOM of an MOSFET (metal oxide semiconductor field effect transistor) is defined as the product of a charge QGD and an on-resistance RDSON.
Further, Japanese Unexamined Patent Publication (Translation of PCT Application) No. 2004-537162 (paragraph 0005) discloses that an FOM of an MOSFET is defined with a specific on-resistance (Ron, sp) associated with a blocking voltage.
Still further, Japanese Unexamined Patent Publication No. 2007-27266 (paragraph 0013) discloses that an FOM of an MOSFET is defined as the product of an on-resistance Ron and a gate-drain capacitance Qgd.
Yet still further, Japanese Unexamined Patent Publication (Translation of PCT Application) No. 2007-512701 (paragraph 0003) discloses that an FOM of an trench MOSFET is defined with an on-resistance (Rds, on) associated with a gate-drain charge density (Qgd).
In this way, the FOM is used as an index for determining the electrical performance of a semiconductor chip or a semiconductor module. However, even though the semiconductor chip or semiconductor module that satisfies desired performance is designed and manufactured based upon the FOM, such production process does not necessarily result in commercially successful products. For instance, even if desired performance is satisfied, a manufacturing cost of semiconductor chip/module may in fact rise. In this way, the FOM can be used to determine performance of the semiconductor chip or the semiconductor module, but cannot be used as commercial criteria.